Combination of Best Promoter and Micellar Catalyst ...

MICELLAR CHEMISTRY

y

Susanta Malik, Aniruddha Ghosh, Kakali Mukherjee and Bidyut Saha

TSD downloaded from www.hanser-elibrary.com by Hanser Verlag (Office) on July 24, 2014 For personal use only.

Combination of Best Promoter and Micellar Catalyst for Cr(VI) Oxidation of Lactose to Lactobionic Acid in Aqueous Medium at Room Temperature In aqueous acidic media, picolinic acid, 2,3-dipicolinic acid, and 2,6-dipicolinic acid promoted Cr(VI) oxidation of lactose to lactobionic acid has been carried out at room temperature. A possible reaction mechanism, which is based on the kinetic results and the product analysis, has been proposed. The anionic surfactant sodium dodecyl sulphate (SDS) and nonionic surfactant Triton-X-100 (TX-100) accelerate the process while the cationic surfactant N-cetylpyridinium chloride (CPC) retards the reaction. Key words: Picolinic acid, lactose, lactobionic acid, Cr(VI), surfactant

Kombination aus dem besten Promotor und dem mizellaren Katalysator für die Cr(VI)-Oxidation von Laktose zur Laktobionsäure im wässrigen Medium bei Raumtemperatur. Die von Picolinsäure, 2,3-Dipicolinsäure und von 2,6-Dipicolinsäure im wässrigen, saurem Medium begünstigte Cr(VI)Oxidation von Laktose zur Laktobionsäure wurde bei Raumtemperatur durchgeführt. Es wurde ein möglicher Reaktionsmechanismus auf Basis der kinetischen Ergebnisse und der Produktanalyse vorgeschlagen. Das anionische Tensid Natriumdodecylsulfat (SDS) und das nichtionische Tensid Triton-X-100 (TX-100) beschleunigen den Vorgang, während das kationische Tensid N-Cetylpyridiniumchlorid (CPC) die Reaktion verzögert. Stichwörter: Picolinsäure, Laktose, Laktobionsäure, Cr(VI), Tensid

1 Introduction

The kinetics and mechanism of oxidation of lactose have been studied in acid medium. Lactose is an important secondary product of the cheese and casein manufacture, whose make up is expected to about 1.2 million tons per year. Because of its low solubility and sweetness, as well as a certain intolerance of some population segment, the use of lactose is limited in many applications [1]. Lactobionic acid (LBA) is a high value-added product obtained from lactose oxidation, with outstanding properties for food and pharmaceutical applications. The main commercial use of LBA is as constituent of the solutions employed for stabilizing organs earlier to transplantation [2]. Lactose is more commonly known as milk sugar since this disaccharide is found in milk. It is composed of b-D-galactose and b-D-glucose. The linkage is between C1 of galactose and C4 of glucose. Hence it is also a reducing sugar [3]. Oxidation by metal is key reaction in organic synthesis. We are interested in the production of lactose to lactobionic acid. Hexavalent chromium

Tenside Surf. Det. 51 (2014) 4

compounds are very powerful oxidizing agent, suitable for important organic synthesis. It is necessary to optimize the use of valuable reagents, the recycling of expensive catalysts and use of environmentally friendly reaction media [4]. Among heavy metals, hexavalent chromium is one of the most common and toxic contaminants in wastewaters arising from various industrial processes. Hexavalent chromium is very carcinogenic [5, 6] and non-aqueous medium is not environmental friendly. The use of large excess of substrate over hexavalent chromium and aqueous medium can solve the problem. A diversity of selective chromium(VI) oxidizing agents as pyridinium chlorochromate (PCC), pyridinium dichromate (PDC), imidazolium dichromate (IDC) etc. have been developed which allow for the oxidation of a large range of compounds [7]. All these reagents required some organic solvents like dichloro methane (CH2Cl2, DCM), acetone (CH3COCH3), dimethyl formamide (Me2NCHO, DMF) which are hazardous in case of skin contact (irritant, permeator), eye contact (irritant), ingestion or inhalation. Solvents in particular make a large contribution to the atmospheric lumber. So we have selected water as a solvent to avoid such hazards. Simple chromic acid oxidation of alcohol is a very slow process [8, 9]. Three representative surfactants (anionic, cationic and neutral) and three promoters picolinic acid, 2,3-dipicolinic acid, 2,6-dipicolinic acid are used for the oxidation of lactose. Micellar catalysis is an improvement in the field of chemical kinetics. During the oxidation of the substrate in the process, the surfactant plays an important role [10] in the path of the reaction, in acidic as well as basic media. The used micellar catalyst can be easily recycled in the reaction several times. Micelles and other types of surfactant aggregates are effective catalysts for a wide range of organic reactions [12] The catalytic effects in such systems are qualitatively understood with compartmentalization and medium effects postulated as essential features of the catalysis.

2 Experimental 2.1

Materials and Reagents

Lactose (SRL, India), K2Cr2O7 (BDH, AR), H2SO4 (BDH, AR), picolinic acid (AR, Aldrich), 2,3-dipicolinic acid (HIMEDIA), 2,6-dipicolinic acid (HIMEDIA), SDS (AR, SRL, India), CPC (AR, SRL, India). Triton-100(AR, SRL) and all other chemical are used in highest purity available commercially. Solutions are prepared in doubly distilled water.

ª Carl Hanser Publisher, Munich

325

Susanta Malik et al.: Combination of best promoter and micellar catalyst for Cr(VI) oxidation of lactose to lactobionic acid


2.2

Procedure and kinetic measurements

Solutions of the oxidant and reaction mixtures contain the known quantities of the substrate (lactose), promoter(picolinic acid, 2,3-dipicolinic acid, 2,6-dipicolinic acid) under the kinetics conditions [lactose]T 4 [Cr(VI)]T and [promoter]T 4 [Cr(VI)]T. The reactions were followed under pseudo first order conditions, using an excess of disaccharide over Cr(VI). Reactant solutions were previously thermostatted and transferred into 1 cm path length cell immediately after mixing. Experiments were performed at 30 8C [9]. The pseudo first order rate constant were calculated from the slopes of the plot of log[Cr(VI)]T versus time (t), which were linear at least for three half-lives. The scanned spectra and spectrum after completion of the reaction were recorded with a UV-VIS spectrophotometer [UV-1601PC (SHIMADZU)]. Under experimental conditions, the possibility of decomposition of the surfactants by Cr(VI) was investigated and the rate of decomposition in this path was kinetically negligible. The optical micrographs are taken in a LEICA DM 1 000 microscope. 2.3

ing the presence of aldonic acid. This was a sign that lactone, which was formed in the rate-determining step, was rapidly hydrolyzed to lactonic acid in a neutral medium [3]. 3 Result and Discussion

The kinetic results showed that the rate of oxidation of lactose was dependent on the first powers of the concentrations of each (substrate, oxidant and acid). The reaction rate increases linearly with an increase in the concentration of lactose showing that the reaction is first order with respect to lactose. The rate of oxidation increases linearly with an in-

Product analysis and stoichiometry

Product analysis was made under mineral acid catalyzed conditions in lactose. Keeping concentration of lactose, in excess over the oxidizing reagent (dichromate), the two solutions were mixed and sulphuric acid was added to maintain the solution pH 2. Under experimental conditions, [lactose]T 4 [Cr(VI)]T (T = total concentration), the oxidation product of lactose, lactones of gluconic acid, was isolated and identified by FeCl3 – HCl blue test. After the completion of kinetic experiment, a portion of the oxidized reaction mixture was treated with alkaline hydroxylamine solution. To prepare a neutral fraction, certain amount of barium carbonate was added to the rest of the reaction mixture. A probing of the resulting mixture with a phenol-colored violet solution of FeCl3 gave bright-yellow coloration, thereby indicat-

Promoter/103 mol dm–3

Figure 1 Representative first-order plot to evaluate the pseudo-first-order rate constant (kobs) for 2,3-dipicolinic acid-promoted Cr(VI) oxidation of lactose in aqueous medium at 30 8C. [lactose]T = 5 · 10–3 mol dm–3, [Cr(VI)]T = 5 · 10–4 mol dm–3, [H2SO4]T = 0.5 mol dm–3; [2,3-dipicolinic acid]T = 50 · 10–4 mol dm–3

Micellar catalyst/103 mol dm–3

None

104 · kobs/s–1

t1/2/h

None

0.2

9.62

PA

5

None

65.15

0.029

2,3-DPA

5

None

74.7

0.0257

2,6-DPA

41.0

0.0469

None

5 CPC

None 1.1

4.13

0.0466

None

SDS

5

26.3

0.0731

None

TX-100

0.24

4.56

0.042

PA

5

CPC

1.1

8.16

0.235

2,3-DPA

5

CPC

1.1

26.35

0.0730

2,6-DPA

5

CPC

1.1

12.9

0.0149

PA

5

SDS

5

15.22

0.0126

2,3-DPA

5

SDS

5

104

0.0185

PA

5

TX-100

0.24

0.504

3.82

2,3-DPA

5

TX-100

0.24

0.986

1.9

2,6-DPA

5

TX-100

0.24

0.46

4.18

[Cr(VI)]T = 5 · 10–4 mol dm–3, H2SO4 = 0.5 mol dm–3, [Lactose]T = 5 · 10–3 mol dm–3, Temp = 30 8C. PA = picolinic acid, 2,3-DPA = 2,3 dipicolinic acid, 2,6-DPA = 2,6 dipicolinic acid. Table 1

326

Pseudo-first order rate constant (kobs) and half life of the reaction in presence and absence of promoter and non-functional micellar catalyst




crease in the acidity of the solution [13]. The pseudo-first-order rate constants (kobs, s–1) were determined from the slope of plots of ln(A450) against time (t) at wave length 450 nm. The pseudo-first-order rate constants (kobs, s–1) are calculated by the slope (Fig. 1) obtained from the plots of ln(A450) versus time (t), divided by the time (t = 60 sec) usual equation as: kobs = slope/time(t). Time (t) = 1 min or 60 second. At t = 60 sec in the denominator of the equation has been divided as the total reaction was monitored for several minutes. The t1/2 values are directly calculated in Table 1 by using relation t1/2 = (ln2/kobs), where ln2 = 0.693, kobs = pseudo-first-order rate constant. The data in Table 1 show kobs for SDS, CPC and TX100 micelle catalyzed reaction to be greater than of corresponding non catalyzed reaction. This observation is also true for promoted path compared to the unpromoted path. It was observed that the reactions of organic compounds were significantly enhanced in the aqueous micellar solutions of ionic surfactants.

If we observe the reaction rate of PA, 2,3-DPA, 2,6-DPA with respect to the blank solution (without promoter and micellar catalyst), then it is seen that the rate enhancement is greater in case of 2,3-DPA due to presence of –COOH group at the 3-position with respect to N–atom in picolinic acid. 3.1

Spectrophotometric analysis of the reaction

3.1.1 UV-VIS Spectra

The slow production of the Cr(III) species was established spectrophotometrically. In the unpromoted path the final color appeared as pale blue (kmax = 594 nm and kmax = 444 nm; Fig. 2a) is quite different from the color found in promoted path which was pale violet (kmax = 578 nm for PA, kmax = 572 nm for 2,3-DPA and kmax = 586 nm for 2,6DPA; Fig. 2b). In the unpromoted path the two bands are observed due to the transitions [14, 15]

(a) Figure 3a Scanned absorption spectra of the reaction mixture at regular time intervals(30 min) [lactose]T = 50 · 10–4 mol dm–3, [Cr(VI)]T = 5 · 10–4 mol dm–3, [H2SO4]T = 0.5 mol dm–3 T = 30 8C

(b) Figure 2 Absorption spectrum of reaction mixture (after completion of reaction): [lactose]T = 5 · 10–3 mol dm–3, [Cr(VI)]T = 5 · 10–4 mol dm–3, [H2SO4]T = 0.5 mol dm–3, T = 30 8C (a) unpromoted: (The spectrum of the chromic sulfate is identical with this under the experimental condition), (b) promoted: (i) [PA]T = 0.005 mol dm–3. (ii) [2,3-DPA]T = 0.005 mol dm–3. (iii) [2,6-DPA]T = 0.005 mol dm–3


Figure 3b Scanned absorption spectra of the reaction mixture at regular time intervals (30). [lactose]T = 50 · 10–4 mol dm–3, [Cr(VI)]T = 5 · 10–4 mol dm–3, [H2SO4]T = 0.5 mol dm–3. [picolinic acid]T = 50 · 10–4 mol dm–3. T = 30 8C

327



kmax = 594 nm for 4A2 g (F) ? 4T2 g (F) and kmax = 444 nm (a 10.1002/kin.20 754 ppeared as shoulder) for 4A2 g (F) ? 4T 1 g (F) of Cr(III) respectively. The spectra of the final solution produced in unpromoted path after completion of the reaction and pure chromic sulphate solution in aqueous sulphuric acid media are almost similar, but it is different in promoted reaction path due to the presence of different types of Cr(III)-species (kmax = 578 nm PA, kmax = 572 nm for 2,3-DPA and kmax = 586 nm for 2,6-DPA; Fig. 2b). This simply suggests that the final Cr(III)-aqua species are Cr(III)-promoter complex. Similar results were reported by earlier workers [16]. In promoted reaction path, there is a hypsochromic (blue) shift for the transition 4A2 g (F) ? 4T 2 g (F) (Fig. 2b) compared to the final solution of the unpromoted reaction path (Fig. 2a). The blue shift for the transition 4A2 g (F) ? 4T2 g (F) in the Cr(III)-promoter complex (Fig. 2b) is due to the presence of the strong field ligand compared to aqueous ligand. The ligands contain one or more heteroatom nitrogen donor sites in the aromatic nucleus. For the Cr(III)-promoter complex [17] the band due to the transition 4A2 g (F) ? 4T1 g (F) merges with a chargetransfer band (Fig. 2b). The appearance of the charge-transfer band at much lower energy (visible range) for the proposed Cr(III)-promoter complex is justifiable because of the favored metal to ligand charge-transfer. The vacant p* (antibonding) M. O. of the ligand (PA, 2,3-DPA and 2,6-DPA) highly facilitates the metal to ligand electron-transfer (MLCT).

Figure 4 Absorption spectrum of reaction mixture with and without promoter (in absence of substrate): (a) [Cr(VI)]T = 5 · 10–4 mol dm–3; [H2SO4] = 0.5 mol dm–3; (b) [Cr(VI)]T = 5 · 10–4 mol dm–3; [H2SO4] = 0.5 mol dm–3; [PA]T = 0.005 mol dm–3; (c) [Cr(VI)]T = 5 · 10–4 mol dm–3; [H2SO4] = 0.5 mol dm–3; [2,3-DPA]T = 0.005 mol dm–3; (d) [Cr(VI)]T = 5 · 10–4 mol dm–3; [H2SO4] = 0.5 mol dm–3; [2,6-DPA]T = 0.005 mol dm–3

Surfactant Cationic

Name of surfactant CPC

The reaction mixtures were scanned in the range 200 nm– 800 nm in both presence and absence of promoter and surfactant at regular time intervals (30 min) to follow the gradual development of the reaction intermediates (if any) and the product. The scanned spectra (Fig. 3a and 3b and supplementary data) indicates the gradual disappearance of Cr(VI) species and appearance of Cr(III). The same is also appeared for micellar catalyzed reactions in presence and absence of promoter. 3.2

The mechanism of the reaction can be divided into two parts: (i) unpromoted path and (ii) promoted path depending upon the substrate, chromic acid hydrogen ion [18]. The variation of substrate, hydrogen ion and promoter concentrations are not shown in this context. Aqueous solutions of chromic acid contain mainly HCrO4– species [19]. (i) Unpromoted path: Unpromoted path is drawn on the basis that the reaction follows first order dependency on [Cr(VI)]T, [lactose]T and second order dependency on [H+] is already established [14, 20]. Detection of the intermediate Cr(VI)-neutral ester formation Differential UV-Vis spectra of mixtures of Cr(VI) and lactose exhibited an absorption band with kmax = 390 nm and k = 265 nm (Fig. 5) consistent with that ascribed to Cr(VI)-neutral ester [20]. At H2SO4 concentration of 0.5 mol dm–3, the

Figure 5 UV-Vis difference spectra of Cr(VI)-lactose solutions, showing the increasing band at 401 nm and 267 nm with increasing [Lactose]: (a) 50 · 10–4 mol dm–3, (b) 100 · 10–4 mol dm–3, (c) 150 · 10–4 mol dm–3, (d) 200 · 10–4 mol dm–3, (e) 250 · 10–4 mol dm–3, (f) 300 · 10–4 mol dm–3, (g) 350 · 10–4 mol dm–3, and (h) 400 · 10–4 mol dm–3; [Cr(VI)] = 5 · 10–4 mol dm–3; [H2SO4] = 0.5 mol dm–3, T = 30 8C. Spectra are taken after 2 min

Method Conductometric

Mechanism

1.1

Anionic

SDS

Conductometric

8.2

Neutral

TX-100

Spectrophotometric

0.24

CMC/mM

Ref.

1.069a

21

9.0b

by conductometric

by fluorimetry at 25 8C

0.231c by surface tension measurement and 0.30d by fluorimetry at 25 8C

22,23 23, 24

a, b, c, d for the literature values of CMC; PEG – polyethylene glycol Table 2

328

CMC values at 30 8C temperature



redox reactions of the studied lactose proceed very slowly with negligible reduction of Cr(VI) within first hours. Thus, at this reaction condition the ester formation step can be distinguished clearly from the electron-transfer reaction. Spectra obtained within 2 min after mixing revealed distinctive peaks at 390 nm and 265 nm. Continued scanning for 30 min showed no further change in the spectra. Effect of the non-functional micellar catalysts on the reaction rate:


The critical micelle concentration (CMC) values of the surfactants CPC, SDS and TX-100 (Table 2) are measured directly with the help of the following methods. The spectacular effect of micelles on organic reactions is due to electrostatic and hydrophobic effects. Electrostatic interactions may affect the rate by influencing the concentration of the reactant(s) near the site of reaction. Scheme 1 leads to the following rate law: kobsðcÞ ¼ ð2=3ÞðK 3 K a k3 k1 ½lactoseT ½PAT ½Hþ 2 Þ= ðk3 þ k1 ÞðK a þ ½Hþ Þ a½lactoseT ½PAT ½Hþ where; a ¼ ð2=3ÞðK 3 K a k3 k1 Þ=ðk3 þ k1 Þ

ð1Þ

The micelles (Fig. 6a–c) of different surfactants SDS, CPC and TX-100 are well-defined roughly spherical and hemi

spherical and they are uniformly distributed among them with no sign of their independent existence in aqueous solution. The corresponding micelles are of roughly nanometer sized [30] as observed in SEM/TEM micrographs. They are observed in 10 lm scale in an optical microscope. Some of the micelles are attached to the inner walls of the empty vesicles as evident from the optical images. They look as if they are diluting away in association with the substrate lactose, on the other hand, produces roughly spherical large micelle (Fig. 6a–c). Partitioning of proton in unpromoted reaction path is highest for anionic surfactant sodium dodecyl sulphate (SDS) due to favorable and very strong electrostatic attraction. SDS forms normal micelles. Thus for SDS, the reaction can go both in aqueous and micellar phase where the active reactants are preferably accumulated [26]. Therefore, SDS facilitates to propagate the reaction in both aqueous and micellar interphases [27]. Small H+ ions can easily penetrate into the anionic SDS micelle due to the effective electrostatic attraction. Active oxidant Cr(VI)-PA (Scheme 1), Cr(VI)-2,3-DPA (Scheme 2) or Cr(VI)-2,6-DPA (Scheme 3) complex react with the substrate to form a ternary complex which experience a redox decompositions in a rate limiting step [28, 29] giving rise to organic product. Positively charged active oxidants are preferably accumulated in the anionic micellar phase of SDS due to electronic

Scheme 1 Chromic acid oxidation of Lactose in presence of picolinic acid


329



attraction. In fact, in the presence of SDS, the reaction simultaneously goes on in both in the micellar phase and aqueous phase and the rate is accelerated in the micellar phase because of the preferential accumulation of the reactants in the micellar phase [30]. In the presence of CPC, although the substrate is partitioned in the micellar phase, the approach of the active oxidants Cr(VI)-PA (Scheme 1),

(a) Figure 6

(b)

Cr(VI)-2,3-DPA (Scheme 2) or Cr(VI)-2,6-DPA (Scheme 3) complexes are repelled. Thus in the presence of CPC, the reaction is toward the aqueous phase which is exhausted in the concentration of the substrate. This leads to the rate retardations. As the micellar head groups of TX-100 are neutral it produces rate enrichment more than water and less than SDS.

(c)

Optical micrograph image of a mixture of lactose and surfactants in water (lactose: surfactant = 20 : 1) (a) SDS; (b) CPC; (c) TX-100

Scheme 2 Chromic acid oxidation of Lactose in presence of 2, 3-dipicolinic acid; kobs(c) = (2/3)k2K3K4[lactose]T[2,3-DPA]T[H+]

330




Scheme 3 Chromic acid oxidation of Lactose in presence of 2,6-dipicolinic acid

Therefore, the reaction rate follows the order: kobs(SDS) > kobs(TX-100) > kobs(water)> kobs(CPC). 4 Conclusion

The combination of 2,3-dipicolinic acid and SDS is the best choice for chromic acid oxidation of lactose to lactobionic acid in aqueous media. Acknowledgements

This work was supported by the CSIR and UGC, New Delhi. References (a)

(b) Figure 7 (a) Schematic representation of neutral ester and H+ in anionic surfactant; (b) schematic representation of partitioning of substrate and active oxidant in anionic surfactant


1. Gutierreza, L. F., Hamoudi, S. and Belkacemi, K.: Selective production of lactobionic acid by aerobic oxidation of lactose over gold crystallites supported on mesoporous silica; Appl. Catal. A 402 (2011) 94 – 103. DOI:10.1016/j.apcata.2011.05.034 2. Nordkvist, M., Nielsen, P. M. and Villadsen, J.: Oxidation of lactose to lactobionic acid by a Microdochium nivale carbohydrate oxidase: Kinetics and operational stability; Biotechnol. Bioeng. 97 (2007) 694 – 707. DOI:10.1002/bit.21273 3. Katre, Y., Singh, M., Singh and A. K.: Kinetics and mechanism of oxidation reaction of lactose by N-Bromophthalimide: Micelles used as a catalyst. Colloid J. 74 (2012) 391 – 400. DOI:10.1134/S1061933X12030167 4. Saha, R., Ghosh, A. and Saha, B.: Combination of best promoter and micellar catalyst for chromic acid oxidation of 1-butanol to 1-butanal in aqueous media at room temperature. Spectrochim. Acta Part A 124 (2014) 130 – 137. DOI:10.1016/j.saa.2013.12.101 5. Saha, R., Nandi., R. and Saha, B.: Sources and toxicity of hexavalent chromium. J. Coord. Chem. 64 (2011) 1782 – 1806. DOI:10.1080/00958972.2011.583646 6. Saha, B. and Orvig, C.: Biosorbents for hexavalent chromium elimination from industrial and municipal effluents. Coord. Chem. Rev. 254 (2010) 2959 – 2972. DOI:10.1016/j.ccr.2010.06.005 7. Sundaram, S. P. and Raghavan, S.: Chromium-VI Reagents: Synthetic Applications. Springer. 2011. DOI:10.1007/978-3-642-20817-1 8. Saha, R., Ghosh, A. and Saha, B.: Micellar catalysis on 1,10-phenanthroline promoted hexavalent chromium oxidation of ethanol. J. Coord. Chem. 64 (2011) 3729 – 3739. DOI:10.1080/00958972.2011.630463 9. Mukherjee, K., Saha, R., Ghosh, A., Ghosh, S. K. and Saha, B.: Combination of best promoter and catalyst for hypervalent chromium oxidation of l-sorbose to lactone of C5 aldonic acid in aqueous media at room temperature. J. Mol. Liq. 179 (2013) 1 – 6. DOI:10.1016/j.molliq.2012.12.012 10. Katre, Y. R., Singh, M., Patil, S. and Singh, A. K.: Effect of cationic micellar aggregates on the kinetics of dextrose oxidation by N-Bromophthalimide. J. Dispersion Sci. Technol. 29 (2008) 1412 – 1420. DOI:10.1080/01932690802313410

331



11. Singh, A. K., Neigi, R., Katre, Y. R. and Singh, S. P.: Mechanistic study of novel oxidation of paracetamol by chloramine-T using micro-amount of chloro-complex of Ir(III) as a homogeneous catalyst in acidic medium. J. Mol. Catal. A 302 (2009) 36 – 42. DOI:10.1016/j.molcata.2008.11.041 12. Basu, A., Ghosh, S. K., Saha, R., Ghosh, A., Mukherjee, K. and Saha, B.: Micellar Catalysis of Chromic Acid Oxidation of Methionine to Industrially Important Methylthiol in Aqueous Media at Room Temperature. Tenside Surf. Det. 50 (2013) 94 – 98. DOI:10.3139/113.110237 13. Banerji, J., Kótai, L., Sharma, P. K. and Banerji, K. K.: Kinetics and mechanism of the oxidation of substituted benzaldehyde with bis(pyridine) silver permanganate. Eur. Chem. Bull. 1 (2012) 135 – 140. 14. Ghosh, A., Saha, R., Mukhejee, K., Ghosh, S. K., Bhattacharyya, S. S., Laskar, S. and Saha, B.: Selection of suitable combination of nonfunctional micellar catalyst and heteroaromatic nitrogen base as promoter for chromic acid oxidation of ethanol to acetaldehyde in aqueous medium at room temperature. Int. J. Chem. Kinet. 45 (2013) 175 – 186. DOI:10.1002/kin.20754 15. Figgis, B. N.: Introduction to ligand fields. Wiley Eastern Limited, New Delhi, India (1966), p. 222. 16. Khan, Z. and Ud-Din, K.: One-step three-electron oxidation of tartaric and glyoxylic acids by chromium(VI) in the absence and presence of manganese(II). Transition Met. Chem. 27 (2002) 617 – 624. DOI:10.1023/A:1019819316240 17. Mukherjee, K., Saha, R., Ghosh, A., Ghosh, S. K. and Saha, B.: Efficient combination of promoter and catalyst for chromic acid oxidation of propan-2-ol to acetone in aqueous acid media at room temperature. Spectrochim. Acta, Part A. 101 (2013) 294 – 305. DOI:10.1016/j.saa.2012.09.095 18. Ghosh, A., Saha, R., Mukhejee, K., Ghosh, S. K., Bhattacharyya, S. S., Laskar, S. and Saha, B.: Selection of suitable combination of nonfunctional micellar catalyst and heteroaromatic nitrogen base as promoter for chromic acid oxidation of ethanol to acetaldehyde in aqueous medium at room temperature. Int. J. Chem. Kinet. 45 (2013) 175 – 186. DOI:10.1002/kin.20754 19. Medien, H. A. A.: Kinetics of Oxidation of Benzaldehydes by Quinolinium Dichromate. Naturforsch. Z. 58b (2003) 1201 – 1205. 20. Saha, R., Ghosh, A., Sar, P., Saha, I., Ghosh, S. K., Mukherjee, K. and Saha, B.: Combination of best promoter and micellar catalyst for more than kilo-fold rate acceleration in favor of chromic acid oxidation of D-galactose to D-galactonic acid in aqueous media at room temperature. Spectrochim. Acta Part A 116 (2013) 524 – 531. DOI:10.1016/j.saa.2013.07.065 21. Bakshi, M. S.: Cetylpyridinium chloride–tetradecyltrimethylammonium bromide mixed micelles in ethylene glycol–water and diethylene glycol–water mixtures. J. Chem. Soc., Faraday Trans. 93 (1997) 4005 – 4008. DOI:10.1039/A703310I 22. Bakshi, M. S., Kaur, N. and Mahajan, R. K.: A comparative behavior of photophysical properties of Pluronic F127 and Triton X-100 with conventional zwitterionic and anionic surfactants. J. Photochem. Photobiol. A 183 (2006) 146 – 153. DOI:10.1016/j.jphotochem.2006.03.008 23. Bakshi, M. S.: Micelle formation by sodium dodecyl sulfate in water-additive systems. Bull. Chem. Soc. Jpn. 69 (1996) 2723 – 2729. DOI:10.1246/bcsj.69.2723 24. Ruiz, C. C., Molina-Bolívar, J. A. and Aguiar, J.: Thermodynamic and structural studies of Triton X-100 micelles in ethylene glycol-water mixed solvents. Langmuir 17 (2001) 6831 – 6840. DOI:10.1021/la010529p 25. Khullar, P., Singh, V., Mahal, A., Kumar, H., Kaur, G. and Bakshi, M. S.: Block Copolymer Micelles as Nanoreactors for Self-Assembled Morphologies of Gold Nanoparticles. J. Phys. Chem. B 117 (2013) 3028 – 3039. DOI:10.1021/jp310507 m 26. Ghosh, A., Saha, R., Mukherjee, K., Ghosh, S. K., Sar, P., Malik, S. and Saha, B.: Choice of suitable micellar catalyst for 2,2’-bipyridine promoted chromic acid oxidation of glycerol to glyceraldehyde in aqueous media at room temperature. Res. Chem. Intermed. DOI:10.1007/s11164 – 013 – 1415 – 6 27. Ghosh, S. K., Basu, A., Saha, R., Nandi, R. and Saha, B.: Kinetics and mechanism of 2,2’-bipyridyl catalyzed chromium(VI) oxidation of formic acid in the presence and absence of surfactants; Current Inorg. Chem. 2 (2012) 86 – 91. DOI:10.2174/1877944111202010086

332

28. Ghosh, S. K., Saha, R., Mukherjee, K., Ghosh, A., Bhattacharyya, S. S. and Saha, B.: Micellar catalysis on 1,10-Phenanthroline promoted chromic acid oxidation of propanol in aqueous media. J. Kor. Chem. Soc. 56 (2012) 164 – 168. DOI:10.5012/jkcs.2012.56.1.164 29. Saha, R., Ghosh, A. and Saha, B.: Kinetics of micellar catalysis on oxidation of p-anisaldehyde to p-anisic acid in aqueous medium at room temperature. Chem. Eng. Sci. 99 (2013) 23 – 27. DOI:10.1016/j.ces.2013.05.043 30. Saha, R., Ghosh, A. and Saha, B.: Micellar catalysis on 1, 10-phenanthroline promoted hexavalent chromium oxidation of ethanol. J. Coord. Chem. 64 (2011) 3729 – 3739. DOI:10.1080/00958972.2011.630463 Received: 03. 02. 2014 Revised: 07. 05. 2014 Bibliography DOI 10.3139/113.110314 Tenside Surf. Det. 51 (2014) 4; page 325 – 332 ª Carl Hanser Verlag GmbH & Co. KG ISSN 0932-3414

y

Correspondence address Mr. Prof. Bidyut Saha Homogeneous Catalysis Laboratory Department of Chemistry The University of Burdwan Golapbag, Burdwan Pin 713104, WB India Mobile: +919476 3416 91 Tel.: +91-3 42-2 53 3913 (O) Fax: +91-3 42-2 53 04 52 (O) E-Mail: [email protected]

The authors of this paper Susanta Malik: He was born in Kalna, Burdwan in 1988. He passed his M.Sc degree from the University of Burdwan in 2011 and got UGC-RGNF fellowship on the year 2012. He is working in my lab in \Bio-remediation" division. Aniruddha Ghosh: He was born in Raniganj, in 1988. He passed his M.Sc degree from the University of Burdwan in 2010 and got NET-UGC fellowship on the year 2010. He is working in my lab in \Bio-remediation" division. Kakali Mukherjee: She was born in Bankura, in 1988. She passed her M.Sc degree from the University of Burdwan in 2011 and got NET-LS fellowship on the year 2010. She is working in my lab in \Bio-remediation" division. Dr. Bidyut Saha: He was born in Birbhum, WB, India in 1975. He obtained his Ph.D degree from Visva Bharati University, India in 2007. He was a visiting scientist for the year 2009 – 2010 in the Department of Chemistry, UBC, Canada. Dr. Saha is presently working as an Assistant Professor in the Department of Chemistry, Burdwan University, India. His area of interests is bioremediation of toxic metal, micellar catalysis and inorganic reaction mechanism. He has already published thirty papers in international journals.
